Small backyard pond keeps filling with water...without rain! Any ideas? (pics)

[The Great Ayam]

I have been working on a small backyard pond for some time now. It's about 4 feet at its deepest. I am not completely finished with it yet, and now I'm noticing something.
There is clay at the deepest part. About a foot of rain has collected. I bucketed the water out TWICE...and both times I returned the next day to find all the water had returned...without any rain.
Any ideas?
I do not believe it is spring fed because it was dry when I was digging. Possibly ground water trapped above the clay?
Anyone else ever have a similar experience?

 

[Vosh Sahaal]

You have created a shallow well.

 

[BBQJOE]

And this is a problem?

 

[The Great Ayam]

And this is a problem?

LOL, BBQJOE. I'm just curious about the science behind the reappearing water. But yes I do want water in it... Just when I'm finished with the project. I have to keep emptying it to work on it. Just curious about the source of the water.

 

[Vosh Sahaal]

It's groundwater. Apparently you have a high enough water table you managed to dig a well.

 

[twisted-acres-farm]

TRY hard to not puncture the clay bottom!! or the water will drain away and could continue to do that when you want it filled. You could also use a small sump pump to work on keeping it dry until your project is completed

 

[The Great Ayam]

Thanks for all the responses. I appreciate it. This is an unexpected yet interesting situation in this project.

 

[wyoDreamer]

You haven't given us much info to go on.
There is a site online that you can check to see the soil types for your area - that may help. It may show that you have clay lenses with perched water, a shallow water table, or you may even a leaky city watermain.
Where are you located? where is the pond - is it in a low spot in the yard? is it downhill from you or your neighbors septic?

 

[NorthTexasWink]

I live with clay soils. When I was landscaping and considering my proposed pond placement, I researched underground water flow mechanics and how to control the groundwater. I'd already built some berms, as I'm on a slope. I learned the berms "bank" some of the groundwater/runoff and slowly release it downhill. The clay subsoil acts as a barrier, keeping most of the water near the surface. I also have a "seep spring" on my property. It isn't a true spring, but is where the accumulated runoff and excess ground water is naturally directed to leak out by the underground formations of rock and clay that make up the large ridge that my property sits on the side of. Hope that makes sense. I've harnessed that outflow of water towards my plantings and and my pond system to help everything stay well watered even during a prolonged dry spell.

Keeping your clay layer intact can save you much labor and expense when trying to seal your pond enough to keep it filled. If you can work with it, I think you'll be happier keeping it natural. You can also learn to direct your pond overflow in ways that benefit you and save water. Good luck! It looks like you've got a good start.

 

[ChocolateMouse]

Yeah, this happens in my area when you dig down about 8 inches-1', depending on how long it's been since it rained last. It's groundwater seepage for sure. It just fills up because of gravity. Water tries it's hardest to move to the lowest point (ocean) and your pond is the lowest point in the immediate vicinity. If you get some good rains it'll probably stay full at some point.